HPV & HPV vaccination: Issues in developing countries.

Cervical cancer is the second-most common cancer in women worldwide causing most cancer related deaths in women in developing countries including India. The most predominant etiological factor for cervical cancer is persistent infection of certain high-risk types of human papillomaviruses (HR-HPVs), while low-risk types are associated with benign cervical lesions and genital warts. In India, the most common (98%) oncogenic types are HPV types 16 and 18 with HPV 16 exclusively (80-90%) prevalent. Two recently developed virus-like particle (VLP) based prophylactic HPV vaccines, quadrivalent Gardasil (HPV 16/18/6/11) and Cervarix (HPV 16/18) offer great promise. Several other therapeutic vaccines are also in clinical trials and are yet to establish their efficacy. The use of already developed VLP vaccines in resource-poor regions is limited by several factors, most importantly the high cost of the vaccine. Therefore efforts are being made in India to develop cost-effective second-generation vaccines. Besides cost, there are several socio-cultural and ethical issues involved with the implementation of already developed vaccines including the acceptability of HPV vaccination by preadolescent girls and their parents in India.

Infection of human papillomaviruses in cancers of different human organ sites.

Clinico-epidemiological and molecular studies have established the casual link between Human Papillomavirus (HPV) infection and cervical cancer as also association of HPV infection with several other cancers. In India, cervical cancer is a leading cancer among women and almost all cases of cervical cancer show prevalence of High Risk (HR)-HPV infection. HPV has been also detected in a significant proportion of oral, esophageal, anal, vaginal, vulvar, and penile cancer and in a small percentage of lung, laryngeal, and stomach cancer in India. Due to lack of organized HPV screening program, insufficient infrastructure and trained manpower and inadequacy in cancer registries, there are not much data available on the countrywide HPV prevalence and its type distribution in different cancers in India. Forthcoming introduction of recently developed HPV vaccines in India given a new urgency to know the prevalence and distribution of various HPV types in different organ sites for the management and monitoring of vaccination program and its impact on prevalence of other cancers. This review, summarizes studies on the prevalence of HPV infection in cancers of different organ sites in India.